The robotics produces Motor Failure or Skipped Stitches Errors when stitching a pattern but not when tracing a pattern.
Stitch Regulator Problem
If the robotics can trace a pattern (move the needle the to-be-quilted pattern without stitching) without error, then the problem lies with the stitch regulator, not with the robotics system.
Monitor the encoders
Stitches are skipped due to inaccurate readings coming from the encoder. Determine at what point on the quilt area the encoder is slipping/lifting off the rail. Bad readings from the encoder are causing the needle to stay down, to display a motor error, or to skip stitches.
Ensure encoders are properly spring tensioned
lift the encoder a half inch or so off the track and let go. Check both encoders to make sure they are spring-loaded and that they are pressing firmly against the track, not just laying there because of gravity.